This invention generally relates to the art of electrical connectors and, particularly, to a modular jack assembly for use in telecommunications equipment.
Modular jack assemblies arc used in telecommunications equipment for mating with telephone-type modular plugs to transmit electrical signals therethrough. A typical modular jack assembly includes a dielectric housing having a receptacle for receiving the modular plug. A plurality of conductive terminals are mounted in the housing, with contact arms cantilevered into the receptacle. A conventional modular jack assembly includes at least eight terminals for engaging eight contacts of the modular plug. A simple eight-terminal modular jack assembly which mates with an eight wire plug is quite reliable and creates few problems.
However, some modular plugs contain only four or six wires, but the four or six wire plugs still are inserted into an eight-wire jack assembly. When this occurs, the outside terminals in an eight-terminal array in the jack assembly are prone to become damaged. This is due to the plastic ends of the plugs outside the four or six wire array contacting some of the jack terminals. The plastic ends cause the terminals to deflect excessively, resulting in a large rotating movement where the terminals are fixed to the jack housing. This large rotational movement causes the terminals to take a permanent set, and those damaged terminals no longer can apply sufficient pressure to the outside wires of a full eight wire modular plug. In addition, with the ever-increasing speed of data transmission, the reduction or elimination of crosstalk has become important for electrical connectors including modular jack assemblies. Crosstalk is a phenomena that occurs when a part of the electromagnetic energy transmitted through one of a plurality of conductors in a connector causes electrical currents in the other conductor or conductors. Various systems have been designed to prevent this crosstalk, such as passing the signals through over-line plates or through traces on a printed circuit board which create a capacitive connection. Heretofore, modular jack terminals have been provided with capacitive plates which were insert molded in the jack housing to maintain registration and location. However, this insert molding process requires a large capital investment.
Still other problems are encountered simply in mounting the tiny modular jack terminals in the very small jack housing. As stated, insert molding is quite expensive for an otherwise simple and inexpensive electrical connector. Mechanically inserting the terminals into the jack housing often results in damage to the tiny and very fragile terminals. The present invention is directed to solving this myriad of problems, including the provision of an eight terminal modular jack assembly which can receive modular plugs of a lesser number of contacts without damaging the jack terminals.
An object, therefore, of the invention is to provide a new and improved modular jack assembly of the character described.
In the exemplary embodiment of the invention, the modular jack includes a dielectric housing means having a mating face. At least one conductive terminal has a body portion mounted in the housing means and a contact arm cantilevered from the mating face of the housing means. The contact arm has a contact portion near a distal end thereof for engaging a contact of an appropriate mating connecting device, such as a modular plug, to flex the contact arm in a direction generally parallel to the mating face. The contact arm has an engaging portion located between the contact portion and the body portion. The housing means has a first wall for engaging the engaging portion of the terminal and a second wall for engaging the contact portion of the terminal to prevent overflexing of the contact arm. According to one aspect of the invention, the first and second walls of the housing means are generally parallel to each other and project generally perpendicular to the mating face of the housing means. The first wall projects form the mating face offset from the contact arm a first distance, and the second wall projects from the mating face offset from the contact arm a second distance.
According to another aspect of the invention, the engaging portion of the contact arm comprises a bowed portion defining a convex surface for engaging the first wall of the housing means. The contact portion of the contact arm comprises, at least in part, a bowed portion defining a convex surface for engaging the second wall of the housing means. The contact portion is bent back onto itself to define the convex surface at a back side of the contact arm, with a contact surface at a front side of the contact arm for engaging the contact of the mating plug.
According to a further aspect of the invention, the housing means include an inner terminal module body in which the terminal is mounted and which defines the mating face of the housing means. An outer housing defines at least one of the first and second walls. As disclosed herein, the first wall is provided on the inner terminal module body and the second wall is provided on the outer housing.
Finally, as disclosed herein, the modular jack assembly includes a linear terminal array on the housing means. At least one of the above-described conductive terminals is located at each opposite end of the linear terminal array.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.